-LRB- CNN -RRB- -- Myanmar 's Supreme Court rejected Friday an appeal by pro-democracy leader Aung San Suu Kyi to overturn her house arrest .

A diplomat who attended the hearing and spoke on condition of anonymity confirmed that the appeal was unsuccessful .

Suu Kyi , 64 , has one final avenue for appeal to a special court in Myanmar 's new capital , Naypidaw .

The Nobel Peace Prize laureate 's house arrest was extended by 18 months last August after an incident in which uninvited American John Yettaw stayed at her lakeside home . Myanmar 's ruling military junta accused Suu Kyi of breaching the terms of her house arrest .

She has been imprisoned or under house arrest for much of the past two decades , since her party the National League for Democracy won a landslide election victory in 1990 . The junta has never recognized the results , but has promised to hold fresh elections this year , although no date has yet been set .

Suu Kyi is disqualified from standing because she was married to a foreigner . The NLD has still to clarify whether it will participate in the vote .

CNN 's Dan Rivers contributed to this report .

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Myanmar 's Supreme Court rejects appeal by democracy leader Aung San Suu Kyi

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Suu Kyi had sought to overturn her house arrest

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Suu Kyi has one final avenue for appeal to a special court

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Her house arrest was extended in August after an uninvited American stayed at her home